Archery bow



INVENToRs W/L/AM /V- FOLBEETH Affare/viva a? PAUL PAPMELEE W. M.FOLBERTH ET AL ARCHERY BOW Filed March 10, 1945 July 8, 1947.

Patented July 8, 1947 UNITED STATES. PATENT OFFICE ARCHERY BOW WilliamM. Folberth, Cleveland, and Paul Parmelee, Cuyahoga Falls, Ohio; saidParmelee assignor to said Folberth Application March 10, -1945, SerialNo. 582,02

14 Claims.

This invention relates to archery bows and more particularly to bows oflaminated or built up construction.

A general object of the invention is to provide an improved bow oflaminated construction which will be eicient and powerful and able toresist the severe strains encountered in service without breaking.Another object is to provide a bow having these desirablecharacteristics and which will be relatively easy and economical tomanufacture.

As is well understood by those skilled in the art, tlie back of a bow,i. e., thatJ portion away from the user, is subject to tension, whilethe front or belly of the bow, i. e., the string side, which is towardthe user, is subject to compression when the bow is bent. Because ofthis fact, for centuries, high gradel bows have been made of yew, forthe heart wood of yew is strong in compression, while th'e sap wood isresilient and strong in tension. The wood of the yew thus combines in asingle piece the two different, characteristics required in bows, and ithas been the practice to make bows of yew with the sap wood toward theback and the heart wood toward the front. This has been an expensive andlaborious process, :for it is necessary to carve the wood very carefullyproperly to follow the grain and to obtain the correct thicknesses ofheart wood and sap wood throughout the bow.

Because of the scarcity of yew and the expense of manufacturing yewbows, modern bows have been made of laminations of different woods gluedtogether in order to obtain the same sort of characteristics found in asingle piece of yew. The laminations ordinarily are relatively thin, andin order to increase the strength and rigidity of the central portion ofthe bow andto provide a grip of convenient size and shape, it has beencustomary to glue additional central laminations to the laminationmaking up the belly of the bow.

This arrangement has necessitated tapering the additional laminations toexposed feather edges; the glued joints at the feather edges of theadded laminations inevitably are regions of weakness in the completedstructure. The central portion of a bow is placed under greatcompressive stresses when the bow is bent or drawn, which compressivestresses must be resisted by the glued joints between the additionallaminations and the main laminations. Also, when an arrow is released,the tips of the bow may bend away from the user far enough momentarilyto imPOSe severe tensile and shearing stresses on the glued joints ofthe additional laminations. This is particularly apt to occur if the bowstring should break, for then there is nothing to restrain the movementof the tips of the bow under th'e influence of their own inertia, exceptthe structure of the bow itself. Thus, in the event of breakage of thebow string of an ordinary laminated bow, failure is apt to occur at theglued joints near the central portion of the bow and particularly at thefeathered end portions of the additional lamination or laminations.Furthermore, the glued joints necessary to secure the laminations aredifficult to make, and the laminations must be feathered accurately andassembled carefully, with the result that the manufacturing operationsare rath'er expensive.

According to the present invention, the difculties heretoforeencountered with laminated bows are eliminated by extending thelamination on the front face or belly of the bow either continuouslythroughout that face, or from the ends of the bow to a point at or nearthe center of the bow where substantially no deflection takes place; andin order to obtain the requisite strength and stiffness in the centralportion as well as to provide a convenient h'and grip, a iiller block isinterposed between the front and rear laminations, spacing them asubstantial distance apart at the center of the bow.

A bow made according to a preferred form of the invention is illustratedin the drawings wherein Figure 1 is a side elevation of a bow embodyingthe invention, the bow being made up or strung; Figure 2 is a similarelevation showing the shape of the bow when unstrung; Fig. 3 is a backelevation of a bow embodying our invention; and Figure 4 is alongitudinal sectional view on an enlarged scale, through the centralportion of the bow.

In Figure 1 the bow indicated generally at I0 is sh'own in solid linesin its strung condition, the dotted lines to the right indicating theshape of the bow when it is drawn or bent. In Figure 2, the bow is notstrung, and the dotted lines to the left indicate the position the tipsII and limbs I2 of the bow may take momentarily if the bow string I4should break as an arrow is discharged. As shown particularly in Figure3, the invention is illustrated herein as adapted to a bow having asighting window or recess l5 in the central portion I6 thereof, thewindow and the arrow rest II being immediately above the grip I8. Thecentral portion I6 is thickened as shown to provide the requisitestrength and stiiiness and to furnish a convenient grip. The thicknessis reduced gradually in both directions, and the limbs I2 of the bow areof substantially uniform thickness and of uniformly decreasing widthfrom the regions I9 to th'e tips. The bow preferably is provided with a.sight 20, adjustable laterally on a slide 2| mounted on track 22.

YIn order to obtain the desired characteristics in the bow, wepreferably employ a laminated construction such as shown best in Figure4. The bow is preferably built up of four laminations, the backlamination 23 being composed of a resilient wood which is strong intension, such as hickory or bamboo, or other materials having thedesired elastic qualities; the front lamination 2l, which is subjectprincipally to compressive stresses, is preferably composed of a strongdense wood such as Osage orange or of other material having similarcharacteristics. 'I'he intermediate laminations 25 and 23 are employedprincipally for the purpose of spacing the front and back laminations aslight distance away from the neutral axis of the bow in order to givethe bow greater power with the use of the same amount of material. Thus,the intermediate laminations may be made of any reasonably strong wood,but a heavy wood should not be employed, for it is desirable to make thebow as light as possible. We have found the heart wood of yew or redcedar to be very satisfactory for this purpose.

While only the central portion is shown on an enlarged scale ir. Figure4, it will be understood that the laminations 23, 24, 25 and 26 are eachof substantially uniform thickness throughout the bow, and theincreasing flexibility of the limbs of the bow is obtained by graduallyreducing the width of the limbs from the regions I3 to the tips. 'I'henecessity of providing the grip portion I8, which may be bound withtwine or other suitable material as shown in the drawings, requires thatthe width of the central portion be reduced. It is desirable todischarge the arrow from a point as near the lateral center line of thebow as possible, and the provision of the sighting window I5 and thearrow rest I'I necessitates a furtherV reduction in the width of thecentral portion of the bow. If the laminations were extended through thenarrow central portion of the bow with the same spacing and thicknessthey have in the limbs of the bow, the bow would be extremely weak atits center. Accordingly, we secure the required strength and rigidity atthe central portion of the bow in spite of its reduced thickness, andalso provide a convenient grip, by interposing between the intermediatelaminations 25 and 26 a reinforcing or spacer member 28. This member,which is preferably composed of a strong, dense wood, which is closegrained so that it will not split easily, such as walnut or beefwood, istapered from its greatest thickness at the center of the bow to knifeedges at its ends as indicated at 29. In the central Dortion thereinforcing member may have a. thickness several times as great as thethickness of the combined laminations, although those skilled in the artwill appreciate that the thickness of the laminations and the thicknessof the reinforcing member may be varied within reasonably wide limits.depending upon the size and strength or weight of the bow.

'I'he several laminations and the reinforcing member are glued orotherwise suitably bonded together throughout their entire contactingareas. Preferably synthetic resin glues are employed- It will be notedthat while the reinforcing member tapers down to knife or feather edgesat its ends, the thin and necessarily relatively weak end portions ofthe reinforcing member are disposed at or very near the neutral axis ofthe bow so that they are not subject to great stresses. Furthermore, theends of the glued joints between the reinforcing member and thelaminations are not exposed. The laminations themselves are preferablycontinuous either from tip to tip of the bow or from the tips toa po' tor points in the central portion of the bow here no substantialdeilection takes place when the bow is in use. For example, thelaminations may be broken in the grip portion of the bow so that thejoints between the ends of the laminations will be covered by thebinding on the grip.

With this construction, the required rigidity of the center portion ofthe bow is obtained by the use of a single spacing .or reinforcingmember which may be glued into place securely because vit is disposed-between the laminations.

All parts of the reinforcing member are nearer the neutral axis of thebow than the laminations, for the reinforcing member extendssubstantially equal distances toward the back and the front of the bow,from the center line of the limbs of the bow at their juncture with thereinforcing member. Thus. the liber stresses in thereinforcing memberare always less than those in the laminations with the result that thereis very little likelihood of breaking the thinned ends of thereinforcing member or of destroying the bond between the reinforcingmember and the laminations.

It will be noted that the surface 30 of the reinforcing member towardthe back of the bow is curved in an arc such that when the bow is fullydrawn the curve in the reinforced central part of the bow corresponds tothe arc of the bow. Thus, as shown in the broken lines in Figure 1, whenthe bow is fully drawn and under greatest stress, the laminations on theback of the bow extend in continuous curves throughout the limbs andcentral portion of the bow with the result that there are no regionswhere the stresses are excessive or unusually great. The reinforcingmember 23 has a straight section as at 3| on the front or belly side ofthe bow, and this straight portion merges into curved portions 32 whichare preferably reversely curved, i. e., concave, as at 33 near the endsof the reinforcing member. The reverse curves insure that thelaminations on the belly side of the bow will also be smoothly curvedfrom the tips of the bow to the central straight portion, again as shownin broken lines in Figure 1. composed of materials especially selectedto enable them to withstand the stresses to which they are subjected,and as the laminations are continuous from the tips of the bow to thethickened central portion where no substantial deflection takes place,there are no glued joints at the ends of the laminations which aresubject to any great stresses. For these reasons, the likelihood offailure is minimized.

Because of their advantageous construction, bows embodying our inventionare durable and not subject to failure even in the event of breakage ofthe bow string. Our bows can be made with the desired characteristics bythe selection of the proper woods and of the proper thicknesses and byproportioning the materials in manners understood by those skilled inthe art. The reinforcing or spacer member interposed between the Thelaminations are y laminations gives the requisite strength and rigidityto the center section of the bow even though the center section isgreatly reduced in 'width in o-rder to provide a sighting window. As

the center section extends both forward and backward from the centerline of the bow, the arrow rest I1 may be disposed on or close to thefrontand-back center line of the bow which makes for accuracy inshooting. These advantages are coupled with economy'of manufacture, forthe laminations may be of substantially uniform thickness throughout,the reinforcing member may be of one piece and there are no exposedgluedjoints or feathered edges. All of these factors contribute tothelease with which bows embodying our invention may be manufactured.

Those skilled in Athe art will appreciate that various changes andmodifications may be made in the preferred form of bow described hereinwithout departing from the spirit and scope of the invention. .It istherefore to be understood that our patent is not limited to thepreferred vform described herein or in any manner other than by the.scope of the appended claims.

We `claim:

1. An archery bow comprising a plurality of laminations including a backlamination composed of an elastic wood adapted to resist stresses intension, a front lamination composed of a strong, dense wood adapted toresist stresses in compression and two intermediate laminations composedof a wood less dense than the Iwood of which the front lamination iscomposed, the laminations being continuous from the tips to at least thecentral portion of the bow, and a wooden reinforcing member interposedbetween said intermediate laminations in the central portion of the bow,the reinforcing member increasing in thickness from substantially knifeedges at its ends to an intermediate thickness great enough to provide aconvenient grip and to substantially increase the strength and rigidityof the central portion of the bow, said laminations and said reinforcingmember being glued together throughout substantially all of theircontacting areas.

2. A bow according to claim 1 wherein the back lamination is hickory`the front lamination is Osage orange,`the intermediate laminations areyew and the reinforcing member is walnut.

3. An archery bow comprising a plurality of laminations including a backlamination composed of an elastic wood adapted to resist stresses intension, a front lamination composed of a strong, dense wood adapted toresist stresses in compression and two intermediate laminations composedof a-wood less dense than the wood of which the front lamination iscomposed, the front and back laminations being continuous from the tipsto at leastthe central portion 0f the bow, and a wooden reinforcingmember interposed between said intermediate laminations in the centralportion of the bow, the reinforcing member increasing in thickness fromsubstantially knife edges at its ends to an intermediate thickness greatenough, substantially to increase the strength and rigidity of thecentral portion of the bow.

4. An archery bow comprising a plurality of laminations including a backlamination composed of an elastic wood adapted to resist Stresses intension and a front lamination composed of a strong, dense wood adaptedto resist stresses in compression, and a reinforcing member interposedbetween said intermediate laminations in the central portion of the bow,the reinforcing member having an intermediate thickness great enoughsubstantially to increase the strength and rigidityA of the centralportion of the bow.

5. An archery bow comprising a plurality of laminations, the laminationsmaking up the limbs of the bow being continuous from the tips thereof atleast to points in the central portion of the bow where no substantialdeflection takes placey and a member disposed between the front and backlaminations in the central portion of the bow for increasing thestrength and rigidity of the central portion and providing a convenientgrip, said member having a thickness at the center of the bowsubstantially greater than the total thickness of the laminations andtapering to feather edges at its ends. the limbs of the bow eing ofsubstantially uniform thickness and de reasing width from the ends ofmember to the ti s of the bow, said laminations and said member beingglued together throughout substantially all of their contacting areas.

6. An archery bow comprising a. plurality of laminations, thelaminations making up the limbs of the bow being continuous from thetips thereof at least to points in the central portion of the bow Whereno substantial deflection takes place, and a member disposed between thefront and back laminations in the central portion of the bow forincreasing the strength and rigidity of the central portion andproviding a convenient grip, said member having a thickness at thecenter of the bow substantially greater than the total thickness of thelaminations and tapering to feather edges at its ends, the limbs of thebow being of substantially uniform thickness, said laminations and saidmember being glued together throughout substantially all of theircontacting areas.

7. An archery bow comprising a plurality of laminations, each laminationbeing of substantially uniform thickness throughout and a memberdisposed between the front and back laminations in the central portionof the bow for increasing the strength and rigidity of the centralportion and providing a convenient grip, the limbs of the bow increasingin width from the tips to regions adjacent the ends of said member andthe central portion being reduced in width and cut away on one side toprovide a. sighting window and an arrow rest, the thickness of the limbsof the bow being substantially uniform from the tips to regions adjacentthe ends of said member, the thickness of the central portion beingincreased by said member, and said front and back laminations beingcontinuous from the tips of the bow at least to regions of said centralportion where no substantial deflection occurs.

8. An archery bow comprising a plurality of laminations, each laminationbeing of substantially uniform thickness throughout and a memberdisposed between the front and back laminations in the central portionof the bow for increasing the strength and rigidity of the centralportion, the central portion being reduced in width and cut away on oneside to provide a sighting window and an arrow rest, the thickness ofthe limbs of the bow bein-g substantially uniform from the tips toreg-ions adjacent the ends of said member, the thickness of the centralportion being increased by said member, and said front and backlaminations being continuous from the tips of the bow at least toregions of said central portion where no substantial deflection occurs.

9. An archery bow comprising a plurality of laminations and a memberdisposed between the front and back laminations in the central portionrest, the thickness of the central portion being increased by saidmember. and said front and back laminations being continuous from thetips of the bow at least to regions 0f said central portion where nosubstantial deflection occurs.

10. An archery bow comprising a front lamination and a back lamination,the laminations being continuous from the tips of the bow at least topoints adjacent the center of the lbow and a. central reinforcing memberdisposed between said laminations and spacing them apart, thereinforcing member extending only through the central portion of the bowwhere no substantial deflection occurs and tapering in both directionsfrom a relatively thick center to very thin edges at its ends, the saidthin edges being disposed substantially on the neutral axis of the bow.

11. A bow according to claim 10 wherein the back lamination is hickoryand the front lamination is Osage orange.

12. A bow according to claim 10 wherein the 8 reinforcing member extendssubstantially equal distances toward the front and back of the bow fromthe center line of the limbs of the bow at their Junctures with saidreinforcing member.

13. A bow according to claim 10 wherein the back surface of thereinforcing member is continuously curved substantially to correspond tothe curve of the bow when fully drawn.

14. A bow according to claim 10 wherein the back. surface of thereinforcing member is continuously curved to substantially correspond tothe curve of the bow when fully drawn, and wherein the front surface ofthe reinforcing member is concave adjacent its ends.

The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Hill Sept. 23, 1941 Number

